1. Field of the Invention
The invention relates to a radiant heating body having a carrier for at least one radiant heating resistor, a plate, disc or the like which covers the radiant heating resistor, and a temperature limiter or temperature monitor.
Radiant heating bodies of that kind usually have a carrier for a heating means which is to be electrically operated and which comprises heating resistors. Such heating resistors are covered by a glass ceramic plate, high-quality steel plate or the like plate or disc, which with its top side serves as a hot plate. By virtue of their design configuration, radiant heating bodies of that kind, together with the glass ceramic plate, form a carrier space which is substantially closed outwardly and in which the radiant heating resistors are fitted. In order to prevent overheating of the glass ceramic plate, temperature limiters or temperature monitors are used in relation to such radiant heating bodies.
2. Discussion of the Prior Art
DE 33 15 657 A1 discloses an electrical cooking appliance with a glass ceramic plate having a central opening with a sleeve which is fitted therein and in which a temperature sensor is disposed. In that arrangement the temperature sensor is held in the sleeve displaceably by a spring force to a position of bearing against an upper abutment, whereby, when the temperature sensor bears against the abutment, it projects somewhat above the surface of the glass ceramic hot plate.
Another design arrangement and configuration of a temperature limiter for a glass ceramic cooking unit is known from EP 0 141 923 B1. In that case the temperature sensor extends preferably substantially along a diameter over the cooking area or however in somewhat laterally displaced relationship with respect to the cooking area. The temperature sensor itself comprises a plurality of bar portions disposed in a unitary, elongate outer tube. The temperature sensor of that design configuration makes it possible to communicate to the temperature sensor the different temperature influences resulting from the at least two heating surfaces, so that the response temperature on the part of the temperature sensor is actually independent of whether one or two heating surfaces are in operation.
In the case of radiant heating bodies or radiant heating means it is fundamentally important and also prescribed by safety requirements that the temperature at the underside of the glass ceramic plate does not exceed a maximum value in order to prevent the glass ceramic plate from being damaged. For that reason, temperature limiters are used, which monitor the set maximum value at the underside of the ceramic glass plate and which ensure that the maximum temperature of for example 600.degree. C. or 700.degree. C. at the underside of the glass ceramic plate is not exceeded.
It is known however that the temperature at the underside of the high-quality or glass ceramic plate is not the same at all points, but depends substantially on the routing configuration of the heating conductor or conductors and the dimensioning thereof. If now a temperature distribution in respect of the high-quality steel or glass ceramic plate is plotted in a chart, it can be seen that there are so-called hot spots which only rarely occur in the detection region of the per se known sensor bar of the temperature limiter.